We will present measurement of dijet angular distribution using variable chi, defined as the exponential of absolute rapidity difference between two leading jets in an event. The measurement was done using dataset collected by the D0 experiment during the 2004-2005 running at the Fermilab Tevatron Collider and corresponds to an integrated luminosity of 0.7 fb-1. The distributions are presented in ten dijet invariant mass bins starting from 0.25 TeV and going all the way over 1.1 TeV. This is the first time in a collider based experiment where we directly probe dijet invariant mass beyond 1 TeV. The data are in good agreement with the prediction of the perturbative QCD, and are used to constrain several models of new physics beyond standard model.